Clang, clang, clang, we passed right under the thumping levers of another vast machine, and so came at last to a wide tunnel, in which we could even hear the pad, pad of our shoeless feet, and which, save for the trickling thread of blue to the right of us, was quite unlit. The shadows made gigantic travesties of our shapes and those of the Selenites on the irregular wall and roof of the tunnel. Ever and again crystals in the walls of the tunnel scintillated like gems, ever and again the tunnel expanded into a stalactitic cavern, or gave off branches that vanished into darkness.

We seemed to be marching down that tunnel for a long time. Trickle, trickle , went the flowing light very softly, and our footfalls and their echoes made an irregular paddle, paddle. My mind settled down to the question of my chains. If I were to slip off one turn so , and then to twist it so .⁠ ⁠…